AWIPS images of the POES AVHRR Cloud Top Temperature (CTT), Cloud Top Height (CTH), and Cloud Type products at 18:46 UTCÂ (below) showed that the coldest CTT value was -86Âº C, with a large area of maximum CTH values of 16 km (much of that overshooting the tropopause, as indicated by the violet color enhancement on the Cloud Type product).

AWIPS images showing comparisons of the 4-km resolution GOES-13 fog/stratus product with the 1-km resolution MODIS fog/stratus product (above) and also the 1-km resolution POES AVHRR fog/stratus product (below) offer further demonstration of the importance of improved spatial resolution for the detection of the small-scale filaments of valley fog that were forming across parts of the Appalachian Mountains region during the pre-dawn hours on 08 October 2010.

Multiple rounds of severe thunderstorms moved northward across southern Arizona on 05 October 2010, producing hail as large as 2.5 inches in diameter, wind gusts as high as 75 mph, and rainfall in excess of 2 inches at some locations (SPC Storm Reports). According to a Phoenix Public Information Statement, the 2.5 inch diameter hail was some of the largest hail ever reported in Arizona.

A 3-panel comparison of visible channel images from GOES-11, GOES-15, and GOES-13 (above; also available as a QuickTime movie) showed the large clusters of convection, some of which moved through the Phoenix area (station identifier PHX). After 18:30 UTC, the GOES-11 satellite was placed into Rapid Scan Operations (RSO) mode, allowing images as frequently as every 5-7 minutes (in contrast to the standard operational 15-minute image interval on GOES-15 and GOES-13).

The first lake-effect snow flurries of the season were observed in the Upper Peninsula of Michigan at Gwinn, Sawyer Airport (station identifier KSAW) on 02 October 2010. An AWIPS image of MODIS 11.0 Âµm IR channel data (above) showed a few disorganized cloud bands over Lake Superior, with the coldest cloud top IR brightness temperature values of -13.5Âº C over the KSAW area.

Looking at the buoy data and the ASCAT winds over Lake Superior (below), the wind speeds over the water were not particularly strong — but the winds at KSAW gusted as high as 36 mph during the day. The could be attributed in part to terrain interaction, as the surface winds encountered a rather abrupt change in topography immediately inland across the Upper Peninsula of Miichigan (where the elevations quickly rise to 1000-1800 feet).

The AVHRR Sea Surface Temperature (SST) product from late in the day on 01 October (below) indicated that SST values across much of the central and eastern part of Lake Superior were in the middle to upper 50s F (around 12 to 15Âº C). With 850 hPa air temperatures of 0Âº C to -5Âº C, the “Delta-T” values were not of sufficient magnitude for the formation of well-defined lake-effect snow bands.